1. Field of the Invention
The present invention relates generally to a display apparatus and a backlight scanning method thereof. More particularly, the present invention relates to a display apparatus for effectively mitigating motion blur and flicker, and a backlight scanning method for the display apparatus.
2. Description of the Related Art
A liquid crystal display (LCD), which is the representative display apparatus, is generally used to display images on a monitor such as television, notebook computer, and desktop computer. Since the LCD cannot produce light by itself, it has to utilize the light illuminated from a separate light source. Hence, by using a backlight illuminating behind an LCD panel generally, the LCD represents images by adjusting transmittance of the light illuminated from the backlight according to the movement of the liquid crystals.
Mostly, the backlight has been driven in a hold type which maintains an ON state all the time when power is applied to the LCD. However, when changing from one image to another image, this backlight driving method causes image smearing, that is, causes motion blurring. To address this drawback, suggested is a scanning method which sequentially turns on backlights from top to bottom.
FIG. 1 depicts a related art scanning method in which a backlight driver is used. A scanning signal generator 110 of the backlight driver 100 generates scanning signals in synchronization with a vertical synchronizing signal of a video signal. Line block drivers 120 drive line blocks of the backlight based on the generated scanning signals.
FIG. 2 depicts scanning signals for driving the respective line blocks. In FIG. 2, the backlight is divided to five line blocks and sequentially scanned. Each line block manages a certain number of lines. Each line block is turned on and off for a unit time. Accordingly, the scanning signal of the line block has one pulse for the unit time.
The related art scanning method can mitigate the motion blur, but cannot effectively reduce flickering. In detail, when the backlight is generally scanned based on the vertical frequency 60 Hz of the video signal of the NTSC standard, flicker is viewable in the motionless images of bright gradation. This is because the human eye is far more sensitive to flicker in this case.